1. Field of the Invention
The present invention relates to a technical field of a generator using a piezoelectric element.
2. Description of the Prior Art
A technology has been proposed which utilizes a piezoelectric effect, by which a mechanical energy of a piezoelectric material is transformed into an electrical energy, and incorporates a piece of the piezoelectric material into a small device for use in generators. A variety of materials have been known, both inorganic and organic, which exhibit the piezoelectric effect. Of these, lead zirconium titanate (PZT)-based ceramic materials have attracted attention as a viable piezoelectric element and made a significant progress toward practical use.
For example, Japanese Patent Laid-Open No. 2001-145375 proposes a generator using piezoelectric elements. This official gazette discloses a structure in which two opposing piezoelectric elements are arranged in a container with an impact member (striking body) disposed between the two piezoelectric elements to reciprocally strike them.
In the construction described above, electricity can be generated by oscillating the container to cause the impact member to strike against the piezoelectric elements. To produce a large electric power as a whole, it is necessary to increase the amount of electricity generated in a single impact or to increase the number of times that the impact member strikes the piezoelectric elements. To increase the amount of electricity generated in a single strike, a steel ball is used as an impact member for increasing distortions of the piezoelectric elements when struck. However, when the container is vibrated to cause the impact member to impact the piezoelectric elements, the steel ball does not bounce but hits the piezoelectric element only once. Hence, in producing a greater amount of electricity as a whole, the problem that needs to be addressed is how efficiently the number of impacting actions can be increased.
Under this circumstance, it is an object of this invention to provide an oscillating-type generator which has an impact member striking against the piezoelectric elements and can efficiently increase the number of impact actions and thereby produce a large amount of electricity as a whole.